1. Field of the Invention
The present invention relates to a switch panel for an electronic device, such as a television receiver.
2. Description of the Related Art
Various electronic devices are known which have outer housings and electronic circuits accommodated within the outer housings. With certain types of these electronic devices, a plurality of actuating buttons are provided on the front panel of the outer housing for controlling the operation of the electronic circuit. One example of this type of electronic device is a television receiver, such as shown in FIGS. 1, 2 and 3.
In FIG. 1, an example of a television receiver cabinet is shown, including a cabinet front 10, a cabinet back 12, and a main circuit board 14. The inside surface of the cabinet front 10 has a button panel 16 having push buttons that extend through openings in the cabinet front 10 for operating the television receiver. The push buttons actuate switches 18 that are mounted on the main circuit board 14. In the illustrated embodiment, the main circuit board is held in position in the cabinet by bosses 20 in the cabinet front 10 which are engaged by fittings 22 that fit thereover and are held by screws 24.
In FIG. 2 is shown a close-up exploded view from the inside of a second arrangement of buttons on an electronic device, such as a television. A button mounting bar 26 is supported on an inside surface of a front panel 28 mounted on a pair of bosses 30 and is held in place by screws 32. A plurality of actuating buttons 34 are provided on flexible members 36 connected to the mounting bar 26. The buttons 34 may protrude out of or be recessed into the inside of the front panel 28 via through-holes 38 formed in the front panel 28.
A plurality of switch elements 40 are mounted behind the respective actuating buttons 34 for operation by the actuating buttons as the buttons 34 are pressed. The switch elements 40 are mounted on a circuit board 42 which includes an electronic circuit either as the main circuit board of the electronic device or as an auxiliary circuit board. The switch elements 40 are connected to the electronic circuit so that when the switch elements 40 are actuated, the electronic circuit performs a pre-set operation conforming to the actuated switching elements 34. When the front portions of the actuating buttons 34 are pressed, the flexible members 36 bend and the switch elements 40 are pressed by the rear ends of the actuating buttons 34. The switch elements 40 are thereby actuated by a pressing movement on the buttons 34.
The circuit board 14 or 42 on which the switches 18 or 40 are mounted is supported separately from the actuating buttons 16 or 34. Since, in the above-described electronic devices, the actuating buttons are generally supported by the outer housing, such as by the mounting bar shown in FIGS. 1, 2 and 3, while the switch elements are mounted on a circuit board that is separately mounted, it is extremely difficult to set the relative distance between the actuating buttons and the switching elements to the correct value. In the embodiment of FIG. 1, the switch elements 18 are on the circuit board 14 supported by a chassis or frame accommodated within the outer housing. In FIGS. 2 and 3, the circuit board 42 is mounted in notched ribs 44 and 46 on the inside walls of the housing. In particular, the front cabinet 28 has a pair of vertical ribs below the openings 38 and notches 48 are formed in the ribs 44. The rear cabinet 12 also has a pair of vertical ribs 46 with notches 48 formed therein. The circuit board 42 is fitted into the notches 48 for positioning in the cabinet.
If the relative positioning between the actuating buttons 34 and the switching elements 40 is not correct, proper actuation of the switching elements 40 by the actuating buttons 34 cannot be achieved. That is, if the distance between the actuating buttons 34 and the switch elements 40 is greater than a desired value, there is a risk that the switching elements 40 will not be actuated when the actuating buttons 34 are pressed. Conversely, if the distance between the actuating buttons 34 and the switch elements 40 is smaller than the desired value, there is a risk that the actuating buttons 34 will be perpetually abutted against the switch elements 40, so that no on/off actuation is possible.
With the known switch panels, assembling is complicated because it is necessary to perform separate assembly operations for mounting the actuating buttons in the outer housing or cabinet and for mounting the switch elements in the outer housing.
In addition, if the electronic device is a television receiver, and if the actuating buttons 34 are arranged below the lower edge of the image display of the television, then the switch elements 40 are arranged below the cathode ray tube (CRT). In such case, if dewing occurs on the CRT, there is a risk that water droplets may be dripped onto the switch elements 40 to interfere with the normal operation of the device.